1. Field of the Invention
The present invention relates generally to improvements to apparatus for driving fasteners into hard surfaces such as concrete, aggregate surfaces, structural elements and similar structures, and more particularly pertains to a new and improved explosive discharge actuated tool which fires an explosive discharge cartridge only upon the muzzle of the tool being forced against the work surface.
2. Description of Related Art
Generally, non-explosive discharge actuated tools that drive fasteners into hard surfaces utilize single fastener loading devices. The desired fastener device is inserted into the muzzle or discharge end of the barrel of the tool. A piston or fastener actuator is slidably disposed in the barrel to be actuated by the gas of an explosive discharge, such as a powder cartridge, to propel the fastener out of the barrel into the structural element or work surface of the structural element.
Single load fastener tools normally retract the fastener actuator or piston and move a new explosive cartridge into the firing chamber in two operational steps. Retraction of the piston to a firing position allows insertion of a fastener at the barrel muzzle end. While such a tool may not be cocked for firing, or a safety mechanism may be activated to prevent forward motion of the firing pin, accidental discharge of a cartridge is still possible. Such accidental discharge could cause injury to a person attempting to load the tool with the fastener element. All of these explosive discharge actuator tools utilize a safety device that prevents accidental discharge by requiring that the barrel muzzle be pressed against the work surface of a structural element in order to enable the trigger on the tool to be pulled and explode the cartridge.
These tools utilize a piston reset method that is not related to the fastener that is loaded into the muzzle of the tool. Furthermore, the tools are required to accept and drive fasteners of various lengths. As a result, when a fastener is loaded into the muzzle, there is usually a space or void separating the drive piston from the fastener. This length of the space varies depending on the length of the fastener being utilized. The space between the piston and the fastener directly affects the driving force and subsequent penetration of the fastener into a work surface. Such explosive discharge actuated tools are very loud, somewhat bulky, and heavy, which causes fatigue during long periods of use.
Heretofore, explosive discharge actuated tools have been somewhat cumbersome, heavy and loud.